Wing-shaped surface mount package for light emitting diodes

ABSTRACT

The bottom metal contacts of a surface mount LED are extended wider than the glue covering the LED. The extensions provide more area for soldering to a motherboard.

BACKGROUND OF THE INVENTION

[0001] (1) Filed of the Invention

[0002] This is a divisional application of patent application Ser. No.09/982,370 filed Oct. 19, 2002, now pending.

[0003] The invention relates to light emitting diodes (LED),particularly to surface mount LED package.

[0004] (2) Brief Description of the Related Art

[0005] Prior art surface mount LED packages, as shown in FIGS. 1, 2 anddisclosed in Taiwan Patent Application No. 089109999 and co-pending U.S.patent application Ser. No. 09/596,907, have only single-side bottommetal exposed for making contact to a motherboard. The metal contactplates 11, 12 are covered with glue 15 on top as shown in FIG. 2. Themetal plates 11, 12 have recesses 14 along the vertical edges as shownin the top view FIG. 1, and also have recesses 17 along the horizontalbottom surfaces of the metal contact plates 11, 12 as shown in FIG. 2.These recesses are for sealing glue to lodge and the hold the structuretogether. The LED 10 is mounted on the first metal contact plate 11. Thetop electrode of the LED 10 is wire-bonded to the second metal contactplate 12 by wire 13.

[0006] As shown in the cross-sectional view FIG. 2 along the sectionA-A′ in FIG. 1, the glue 15 fills up the recesses 17 at the bottomsurface of the package and the recess 14 along the vertical sides of thepackage to solidify the structure. This structure only exposes thebottom surfaces of metal contact plates 11, 12 not occupied by therecesses for soldering purpose. This limited area for soldering reducesthe reliability of the contact.

SUMMARY OF THE INVENTION

[0007] An object of this invention is to improve the reliability ofsoldering of a surface mount LED package to a motherboard. Anotherobject of this invention is to increase the soldering area of a surfacemount LED package to a motherboard.

[0008] These objects are achieved by adding extensions to the metalcontacts beyond the borders of the glue covering the LED. The extensionprovides more areas for the contact to be soldered to a motherboard.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0009]FIG. 1 shows the top view of a prior art LED package.

[0010]FIG. 2 shows the cross-sectional view of FIG. 1.

[0011]FIG. 3 shows the wing-shaped contacts of the present invention.

[0012]FIG. 4 shows the covering of the solder over the contactextensions.

[0013]FIG. 5 shows the glue covering the bottom surfaces of thecontacts.

[0014]FIG. 6 shows the glue covering up to the bottom surfaces of thecontacts.

[0015]FIG. 7 shows the bottom contacts with rectangular recesses.

[0016]FIG. 8 shows the bottom contacts with polygonal recesses.

[0017]FIG. 9 shows the glue covering below the bottom surfaces of thecontacts.

[0018]FIG. 10 shows through holes in the contact metals for the glue toflow through and solidify.

[0019]FIG. 11 shows roughened surfaces of the contact metals forincreasing the gluing area.

[0020]FIG. 12 shows a cup shape metal for focusing the light from theLED.

[0021]FIG. 13 shows a package for mounting a LED with two topelectrodes.

[0022]FIG. 14 shows a package for mounting a LED with two bottomelectrodes.

DETAILED DESCRIPTION OF THE INVENTION

[0023]FIG. 3 shows the basic structure of the present invention. A LED20 with a bottom electrode is mounted on a contact metal plate 21serving as first terminal. The top electrode of the LED 20 iswire-bonded to a second contact metal plate 22. The contact metalplates, 21, 22 have recesses 27. The LED 20 and a portion of the topsurface of the metal content are covered and sealed with glue 25,leaving extensions B of the metal plate 21, 22 uncovered. Duringsealing, the glue also fills the recesses 27 to solidify the sealedstructure. The extensions B extend outside the sealed area, and allowmore soldering area 26 for making contacts to a motherboard as shown inFIG. 4. Thus, the solderability of the contacts to a motherboard isimproved.

[0024]FIG. 5 shows a second embodiment of the invention. The structureis similar to FIG. 4 except that the glue 25 seals below the bottomsurfaces of the metal plates 21, 22 by a depth C. Thus the structure ismore fully sealed by the glue 25. The extensions beyond the sealed arearemains available to be soldered to a motherboard.

[0025]FIG. 6 shows a third embodiment of the invention. The structure issimilar to FIG. 3 except that the top surfaces of the metal contactplates 211, 221 are flat. The bottom recesses 271 of such a structurecan be fabricated by chemical or machine etching.

[0026]FIG. 7 shows a fourth embodiment of the present invention. Thestructure is similar to FIG. 6, except that the recess 37 at the bottomof the metal plates 31, 32 is rectangular in shape. The rectangularrecess 371 holds more glue 35 to further solidify the structure.

[0027]FIG. 8 shows a fifth embodiment of the present invention. Thestructure is similar to FIG. 6, except that the recess 371 at the bottomof the metal plates 311, 321 is of polygonal shape. The polygonal recess371 holds more glue 35 to further solidify the structure

[0028]FIG. 9 shows a sixth embodiment of the present invention. Thestructure is similar to FIG. 8, except that the glued area below therecesses 371 at the bottom of the metal plates 311, 321 is made widerthan the width of the glued area 35 on top of the over the LED 20. Theextra widths D outside the recess 371 area increase the distance betweenthe soldering spots on a motherboard, thus avoiding the likelihood ofshort-circuiting between solders.

[0029]FIG. 10 shows a seventh embodiment of the invention. The structureis similar to FIG. 3, except that two through holes 381 are insertedfrom the top surfaces of the metal plates 321, 311 to the bottom recess27 (not shown). The through holes allow glue 25 to flow into the throughholes 381, thus further solidifying the structure.

[0030]FIG. 11 shows an eighth embodiment of the invention. The structureis similar to FIG. 10, except that the top surfaces 382 of the metalplates 311, 321 are roughened. The roughened surfaces increase the gripof the glue to the structure to further solidify the structure.

[0031]FIG. 12 shows a ninth embodiment of the invention. The structureis similar to FIG. 3, except that the glue 35 on top of the metal plates21, 22 forms a cup 39 to expose the LED 20. The cup surface help focusthe light emitted from the LED 20.

[0032]FIG. 13 shows a tenth embodiment of the present invention. Thestructure is similar to FIG. 8, except that the LED 201 has two topelectrodes. The LED 201 straddles over the metal plates 31, 32 and iswire-bonded to these plates respectively by wires 131 and 132.

[0033]FIG. 14 shows an eleventh embodiment of the invention. Thestructure is similar to FIG. 8, except that the LED 202 has two bottomelectrodes. The LED straddles over and are bonded to the metal plates31, 32.

[0034] While the preferred embodiments of the invention have beendescribed, it will be apparent to those skilled in the art that variousmodifications may be made in the embodiments without departing from thespirit of the present invention. Such modifications are all within thescope of this invention.

1. A surface mount light emitting diode (LED) package, comprising: alight emitting diode having a first electrode and a second electrode; afirst metal contact plate having a first bottom recess, mounted withsaid LED and connected to said first electrode; a second metal contactplate having a second bottom recess and connected to said secondelectrode; a glue covering said LED, said first bottom recess and aportion of the top surface of said first metal contact plate, saidsecond bottom recess and a portion of the top surface of said secondmetal contact plate; and extensions of said first metal contact plateand said second metal contact plate outside the borders of said glue toprovide contact and soldering areas to a motherboard, wherein the firstmetal contact plate and the second metal plate each have through holesfor said glue to deposit.
 2. The surface mount LED package as describedin claim 1, wherein the overall dimension of said first metal contactplate orthogonal to said extensions is equal to that of said glue. 3.The surface mount LED package as described in claim 1, wherein theoverall dimension of said second metal contact plate orthogonal to saidextensions is equal to that of said glue.
 4. A surface mount lightemitting diode (LED) package, comprising: a light emitting diode havinga first electrode and a second electrode; a first metal contact platehaving a first bottom recess, mounted with said LED and connected tosaid first electrode; a second metal contact plate having a secondbottom recess and connected to said second electrode; a glue coveringsaid LED, said first bottom recess and a portion of the top surface ofsaid first metal contact plate, said second bottom recess and a portionof the top surface of said second metal contact plate; and extensions ofsaid first metal contact plate and said second metal contact plateoutside the borders of said glue to provide contact and soldering areasto a motherboard, wherein the glue on top surface of the first metalcontact plate and the top surface of said second metal contact plate areroughened to increase the grip of the glue of the glue.
 5. The surfacemount LED package as described in claim 4, wherein the overall dimensionof the first metal contact plate orthogonal to said extensions is equalto that of the glue.
 6. The surface mount LED package as described inclaim 4, wherein the overall dimension of the second metal contact plateorthogonal to said extensions is equal to that of the glue.